The fields of forensics, paternity testing, tissue typing, and personalized medicine routinely use DNA-based techniques for identity determinations, genotyping, phenotypic prediction, and in the prediction and/or prevention of disease. The use of DNA to establish or disprove a defendant's connection to a crime scene sample has been pivotal in analysis of the evidence in criminal proceedings. Frequently, it is not only the autosomal DNA, but DNA associated with the sex chromosomes, X and/or Y, in establishing a defendant's guilt or innocence.
Amelogenin is a protein involved in the production of tooth enamel. In many mammals there exists a copy of the gene on the X chromosome (AMELX) and another copy on the Y chromosome (AMELY). Differences in the Amelogenin DNA sequence between the sex chromosomes have allowed the development of gender determination tests. The differences are easily discerned in a polymerase chain reaction (PCR) in which a single primer pair simultaneously amplifies the DNA from each chromosome revealing different sized fragments. A PCR primer pair can be designed to flank a 6 basepair (bp) deletion found in the amelogenin gene on the X chromosome. The resulting PCR fragment on the X chromosome is 6 bp shorter than the corresponding Y chromosome's fragment.
Accurate DNA analysis has both solved missing persons and exonerated the innocent. The adoption of DNA test results has established DNA-base methodologies as a standard investigative, diagnostic or prognostic tool depending on the application. Alterations in the DNA sequence can occur via mutations, polymorphisms or re-arrangements, for example. The identification of such alterations can be useful in the continued effort to maintain the sensitivity, specificity, quality and reliability of DNA-based technologies. Thus, there exists a need in the art, to improve DNA-based technologies based on the discovery of a new variation in a DNA sequence.